Colorectal cancer is the leading cause of cancer related mortality in the western world. Deaths from colorectal cancer can be prevented through effective screening. There is no uniformly agreed specific screening test or panel that helps direct clinical decision making. Recent studies have defined specific antibody responses to tumour related antigens in patients with cancer. Since these antibodies are often triggered by changes in the structure or expression of self proteins in tumour cells, they may serve as potential immunological markers of cancer.
Various technologies have been used to identify cancer-specific antibodies. Phage display offers a powerful platform to identify antibody signatures. However, phage display technology is labour intensive and peptides expressed by phages often do not correspond to native antigens, thus limiting identification of molecular targets in cancer. Several groups have used proteomics approaches to identify tumour antigens. These methods largely rely on tumour cells as a source for potential antigen. Detection of low abundant proteins and membrane proteins is problematic with this approach. The recent advent of large protein arrays provides a unique opportunity to profile antibody signatures from libraries containing thousands of different proteins. A significant advantage of large protein arrays is that complex, antibody repertoires from cohorts of patients can be easily identified.